OK.... a little bit of thought.
What we are trying to do is generate these 14-plus-9 octdoku/vanilla sudoku puzzles.
For a long while we have randomly made new 17-puzzles and they are still being found. Can we get them all ?
By making these oct-duku puzzles with 14 clues we can very easily search for a 17. Almost all 17s have 3 of one particular clue value.
It has to be easier making these 14 octuku puzzles. [3 less clues, 9 less spaces and 1 less clue value]
gsf has made and canicalized the 13-plus-9 and 14-plus-9 puzzles from gordons list.
We
can also get these puzzles from these here -
[18-puzzles with a 14 plus 4 configuration] [********4]
[19-puzzles with a 14 plus 5 configuration] [********5]
[20-puzzles with a 14 plus 6 configuration] [********6][?exists]
they are not common compared to other puzzles with n-clues.
These all do exist. - If you take a 17-puzzle with a diagonal pattern of the same clue value eg in B1B5B9 - replacing these 3 clues of the 9 rookery with the other 6 always gives a non-minimal puzzle and sometimes gives a 20-clue minimal puzzle with [********6]
We shouldnt attempt the 14-plus-9s untill we improved our method, and perhaps not before we can show we have all the 13-plus-9 octdoku.
These will all come from the 18-puzzles with [********5] distribution
optimizationIt cant be wrong to fix one clue.
It cant be wrong to always be able to find a "gap" in a puzzle.
I believe all puzzles must have a clue like the 1 at r1c7 [not proven]
ie there is a box like
- Code: Select all
+---+
|1**|
|...|
|9..|
+---+
maybe this can be improved on.
- Code: Select all
+---+---+---+
|9**|***|1**|
|...|9..|...|
|...|...|9..|
+---+---+---+
|.9.|...|...|
|...|.9.|...|
|...|...|.9.|
+---+---+---+
|..9|...|...|
|...|..9|...|
|...|...|..9|
+---+---+---+
always pick all the 9s
always pick the 1 at r1c7 and
never pick any of the clues in r1c2-r1c6 and r1c8 and r1c9
- Code: Select all
+---+---+---+
|987|654|123|
|...|9..|...|
|...|...|9..|
+---+---+---+
|.9.|...|...|
|...|.9.|...|
|...|...|.9.|
+---+---+---+
|..9|...|...|
|...|..9|...|
|...|...|..9|
+---+---+---+
In the two types of 18-puzzles I found at random - those with [011222235] and those with [011122335]
In both we
"only" have to iterate 12 clues with 7 clue values over ~ 55 positions each. [still too much]
For now I will look at the incidence and configuration of possible
[********5]&[********4] for the 18s
[********5] for the 19s
[********6] for the 20s and poss 19s
C